The account of the construction of Hezekiah's water tunnel under Jerusalem by King Hezekiah shortly before the city was besieged by Sennacherib in about 701 BC is described in 2 Kings 20:20 and 2 Chronicles 32:2-4, 30. (Incidentally modern radiometric dating of the Siloam Tunnel in Jerusalem by a team led by Amos Frumkin of the Hebrew University of Jerusalem shows that it was excavated about 700 BC and can thus be safely attributed to the Judean King Hezekiah.)

“As for the other events of Hezekiah's reign, all his achievements and how he made the pool and the tunnel by which he brought water into the city, are they not written in the book of the annals of the kings of Judah?” 2 Kings 20:20

“When Hezekiah saw that Sennacherib had come and that he intended to make war on Jerusalem, he consulted with his officials and military staff about blocking off the water from the springs outside the city, and they helped him. A large force of men assembled, and they blocked all the springs and the stream that flowed through the land. "Why should the kings of Assyria come and find plenty of water?" they said.” 2 Chronicles 32:2-4.

“It was Hezekiah who blocked the upper outlet of the Gihon spring and channeled the water down to the west side of the City of David. He succeeded in everything he undertook.” 2 Chronicles 32:30. (Second Chronicles 32:30 also cites the flow of the water from east to west)

The Assyrian empire stretched from the Persian Gulf, up toward the Black Sea, penetrating along the Nile River in Egypt, built up by the most highly developed, specialized war-machine of its time, destroying even the northern kingdom of Israel. In 700 BC Judah stood alone, a single enclave that had not been defeated, bracing itself for the inevitable offensive. Jerusalem was particularly vulnerable because its only permanent water supply, the Gihon spring, which had sustained the city’s existence for thousands of years, was located outside the city walls. A marauding enemy that controlled the Gihon spring could overwhelm the inhabitants very quickly for lack of water. (Hezekiah's concern about an impending military threat is evidenced by the remnants of a wall that expanded to the south and west, considerably beyond the boundaries of the City of David. See Footnote). Now a particularly fierce and bloodthirsty army who had captured the ten northern tribes of Israel and many cities in Judah were marching toward Jerusalem

The Gihon spring also has a fascinating history. See Gihon in this section.

Pool Of Siloam

Hezekiah, recognizing the need to preserve the city's only source of fresh water, undertook an incredibly ambitious, massive, risky project…. A tunnel, hewn from both ends simultaneously, probably along the course of a natural fissure in the rock was a rather amazing feat of engineering for the time, especially since it was constructed without the use of intermediate shafts, an addition which would have provided air, light, food and water to the laboring workmen and made it easier for them to meet up. Digging this tunnel was far from a simple matter considering that work was carried out in the depths of the earth, with minimal lighting by oil lamps, and with little oxygen. Its goal was to channel the Gihon Spring waters from the Kidron Valley, through the bedrock under the hillside of the City of David, into a pool that lay within Jerusalem's walls, and out of the reach of the Assyrians, thus keeping a steady supply of water pumping into Jerusalem during Sennacherib’s anticipated siege. It also made it very difficult for a conquering army to mount a successful siege on Jerusalem with the main local water source was cut off. (The entrance to the spring in the Kidron Valley was skillfully disguised). Even today, the serpentine tunnel delivers water from the Gihon Spring to the Siloam Pool, 500 metres away.

This tunnel, discovered in the 19th century, is a third of a mile long, (approximately 1,800 feet) usually less than three feet wide. It winds in an S-shape from the Gihon Spring, an important site in Old Testament Jerusalem, to the Pool of Siloam, an important New Testament site (in the New Testament, a blind man was told by Jesus to go wash his eyes in this pool (John 9:1–12).

The builders of the tunnel left their own description of the work engraved in the rock wall near the tunnel outlet into the Pool of Siloam. The inscription (called the Siloam Inscription) was found in 1880 and is now in Archaeological Museum, Istanbul, Turkey. It reads:

"... the tunneling through. And this is the account of the tunneling through. While [the workmen raised] the pick each toward his fellow and while there [remained] to be tunneled [through, there was heard] the voice of a man calling to his fellow, for there was a split in the rock on the right hand and on [the left hand]. And on the day of the tunneling through the workmen stuck, each in the direction of his fellow, pick against pick. And the water started flowing from the source to the pool, twelve hundred cubits. And the height of the rock above the head of the workmen was a hundred cubits.".

(The inscription stated that the tunnel was 1,200 cubits in length, which indicates that the ancient cubit was approximately 18 inches long).

The siege of Jerusalem and the campaign of Sennacherib are recorded on the University of Chicago Oriental Institute's six-sided clay artifact called the Prism of Sennacherib, also known as the Taylor Prism. (Discovered in Nineveh in 1830 by a British colonel called R. Taylor).The prism contains six columns covered by over 500 lines of writing. On the six inscribed sides of this clay prism, King Sennacherib recorded eight military campaigns undertaken against various peoples who refused to submit to Assyrian domination. Part of the text on the Taylor Prism has Sennacherib’s account of what happened in his military tour of Judah.

“As to Hezekiah, the Jew, he did not submit to my yoke, I laid siege to 46 of his strong cities, walled forts and to the countless small villages in their vicinity, and conquered (them) by means of well-stamped (earth) ramps, and battering-rams brought (thus) near (to the walls) (combined with) the attack by foot soldiers, (using) mines, breeches as well as sapper work. I drove out (of them) 200,150 people, young and old, male and female, horses, mules, donkeys, camels, big and small cattle beyond counting, and considered (them) booty. Himself I made a prisoner in Jerusalem, his royal residence, like a bird in a cage. I surrounded him with earthwork in order to molest those who were leaving his city’s gate”.

Compare this with 2 Chronicles 32:1: “Sennacherib king of Assyria came and entered Judah; he encamped against the fortified cities....”

Lachish:The Bible tells us very little about the siege of Lachish.

“After this Sennacherib king of Assyria sent his servants to Jerusalem while he was besieging Lachish with all his forces with him, against Hezekiah king of Judah and against all Judah who were at Jerusalem…” (2 Chronicles 32:9)

Then the king of Assyria sent Tartan and Rab-saris and Rabshakeh from Lachish to King Hezekiah with a large army to Jerusalem. So they went up and came to Jerusalem…” (2 Kings 18)

The Relief:One of the most exceptional artifacts found among the ruins of Nineveh was a wall relief (covering almost an entire wall) depicting Sennacherib’s defeat of the city of Lachish. He apparently considered his victory at Lachish of great consequence. (Archaeological digs at the city of Lachish bear out the details of Sennacherib’s wall relief, including enormous sloping siege ramp thrown up against the city walls south of the gate).

What is particularly interesting is that The Assyrians had a vast army and, according to the Taylor Prism, had conquered ‘46 outlying cities’, ‘walled forts’ and ‘countless small villages’. It even talks about Hezekiah being shut up in Jerusalem (“Himself I made a prisoner in Jerusalem, his royal residence, like a bird in a cage”) but the silence is deafening as far as any conquest of Jerusalem is concerned. This is particularly odd considering how much was made of the Lachish victory. Defeat of the capitol Jerusalem would have commanded far more attention than the triumph over Lachish. The Bible tells us that Jerusalem, though completely surrounded by the Assyrian empire, was not engulfed by it, which is borne out by the evidence of silence..

The Deliverance: All of which begs the question.. How did the Israelites withstand the might of the powerful Assyrian army? A couple of verses in Isaiah and Chronicles hold the answer..

“Then the angel of the LORD went out and struck 185,000 in the camp of the Assyrians; and when men arose early in the morning, behold, all of these were dead”. Isaiah 37:6

“And the LORD sent an angel who destroyed every mighty warrior, commander and officer in the camp of the king of Assyria. So he returned in shame to his own land. And when he had entered the temple of his god, some of his own children killed him there with the sword” 2 Chronicles 32.

"The combination of the prophetic counsel of Isaiah to not surrender, the leadership of Hezekiah to fortify the city and provide fresh water, and the divine, sovereign activity in slaying the hosts of the Assyrian army outside the walls of Jerusalem enabled the survival of this nation," (Claire Pfann, a professor of biblical studies at Jerusalem's University of the Holy Land)

Incidentally Sennacherib died precisely as the Bible says he did.. Assyrian records note that Sennacherib died at the hands of his own sons.

Footnote

Assyrian Records were very extensive and detailed: Sennacherib’s grandson, Ashurbanipal, not only built palaces in the city, but established the first private library in his palace, which has provided more information about the ancient world than any single discovery made in Biblical lands.

Hezekiah’s Wall This is a portion of the wall in Jerusalem that Hezekiah built in preparation for Judah's rebellion against Assyria. The smaller stone structure to the right is a house that was destroyed when building the wall. The remains of this wall was discovered by Avigad in the Jewish Quarter of the Old City in 1970. It is about 23 feet thick and still stands up to 10 feet tall.

There is some evidence that the prophet Isaiah was not too happy that some houses were destroyed to build the wall.

And ye have numbered the houses of Jerusalem, and the houses have ye broken down to fortify the wall. Isa 22:10